A modification on 3S criterion and simplified elastic-plastic ratcheting analysis in ASME VIII-2. (December 2020)

• Record Type: Journal Article
• Authors: Shen, Jun; Lu, Ming-wan; Bao, Hongchen; Liu, Yinghua
• Is Part Of: International journal of pressure vessels and piping. Volume 188(2020)
• Publication Date: 2020-12
• Subjects: Ratcheting assessment -- Elastic stress ratcheting assessment -- 3S criterion -- Elastic ratcheting assessment -- Thermal stress ratcheting; Pressure vessels -- Periodicals; Pipe -- Periodicals; Récipients sous pression -- Périodiques; Tuyaux -- Périodiques; Pipe; Pressure vessels; Periodicals; 681.76041
• DOI: 10.1016/j.ijpvp.2020.104215
• Languages: English
• ISSNs: 0308-0161

Abstract

Abstract: Ratcheting is a common and important failure mode in pressure vessels. ASME VIII-2 2019 edition provides two kinds of ratcheting assessment methods——the elastic stress ratcheting assessment (paragraph 5.5.6) applied to the design by elastic stress analysis and the elastic-plastic ratcheting assessment (paragraph 5.5.7) applied to the design by elastic-plastic stress analysis. This paper focuses on the elastic stress ratcheting assessment, which includes again two methods——the elastic ratcheting analysis (paragraph 5.5.6.1), i.e. the 3S criterion, and the thermal stress ratcheting assessment (paragraph 5.5.6.3). This article reviews the development history of 3S criterion and discusses its applicable scope. The study found that the 3S criterion is not a complete elastic ratcheting assessment criterion, when the primary membrane stress range exceeds two-thirds of the cyclic yield stress, i.e. (2/3) S y, the ratcheting assessment based on 3S criterion is unsafe for some situations. When the general primary membrane stress P m and the local primary membrane stress P L, which allowable limit exceeds (2/3) S y, are applied simultaneously, there is still the possibility of ratcheting failure in the structure even if the 3S criterion is met. As an extension of the 3S criterion, a complete and safe criterion on three-dimensional elastic ratcheting assessment is proposed in this paper. In order to avoid the inconvenience of partition assessment, a simplified thermal stress ratcheting assessment method based on double checking surfaces is proposed. It is a simple and conservative assessment method. Finally, elastic ratcheting analysis, thermal stress ratcheting assessment and simplified elastic-plastic analysis in ASME VIII-2 are integrated, a universal elastic stress ratcheting assessment is proposed. Graphical abstract: Image 1 Highlights: A complete and safe criterion on three-dimensional elastic ratcheting assessment is proposed. A simplified thermal stress ratcheting assessment method based on double checking surfaces is presented. A universal method of elastic stress ratcheting assessment is proposed. A detailed comparison between 3S criterion and thermal stress ratcheting assessment is made. Examples of new elastic stress ratcheting assessment methods are presented.